Hugo brewer



} STATES HUGO BREWER, OF DUISBURG, GERMANY.

PROCESS OF UTILIZING WASTE LYE.

SPECIFICATION forming part of Letters Patent No. 544,499, dated August13, 1895.

Application filed March 21, 1895. Serial No. 542,615. (No specimens.)

' clear, and exact description of the invention.

My invention relates to the utilization of the lyes resulting from thelixiviation of ores or residues of such after their chlorinatingroasting; and it consistsin a novel process or method of treating saidlyes, as will now .be fully described.

'In'the chlorinating roasting of ores or residues of such sodium chloridis generally employed, and this has heretofore been lost in the lyesresulting from the lixiviation of such ores. Many attempts have beenmade to re cover the constituents of the lyes, principally the morevaluable metals they-may contain, with the result of a final undesirableand trou: blesome Waste lye, so that, as a rule, the utilization orworking up of these lyes has been deemed impracticable or of littleadvantage,

particularly inso far as lyes containing zinc are concerned.

My invention has for its object a process or method of treating saidlyes wherein the production of undesirable or obnoxious final waste lyesis entirely avoided, and whereby substantially all of the more valuablemetals contained in the lye, together with the sodium and chlorine, maybe economically and profitably recovered, such sodium and chlorine beingreconverted into sodium chlorid for fur ther use in the process ofchlorinating roasting. 1

The object of my invention is attained by converting the sulphates inthe lye into chloride by the addition thereto of a quantityof calciumchlorid equivalent to the quantity of sulphuric acid in the sulphates.The calcium sulphate precipitate formed, which can be utilized for anydesired purpose-as, for instance, in the form ofplaster-of-paris-contains the sulphuric acid of the sulphates togetherwith the calcium of the calcium chlorid used. After removal of thesulphate of calcium the lye contains zinc, and generally other metals inthe form of chloride instead of sulphates, and also the sodium of thesodium chlorid used in the roasting of the ore. The above-describedconstituents of the lye can be removed and the sodium reconverted into achlorid by means of the chlorine recovered for further use in theroasting process, While the calcium may be'reconverted into a chloridalso, and used over again in the process of conversion of the sulphates.

The following example will clearly show the manner of carrying out myinvention: Zinc blende or other zinciferous material is subjected to theusual chlorinating roasting either per se or with additions of pyrites,or

oxid of iron or purple ore, the roasted ore being then lixiviated inwater. To the lye or liquor, which contains essentially sodium sulphate,chlorid of zinc, sodium chlorid, and sulphate of iron, besides othersalts of metals, as manganese, cobalt, nickel, silver, 850., I add aquantity of calcium chlorid equal to the quantity of sulphuric acidpresent. The sodium sulphate, as well as the sulphates of the othermetals present in the lye, are converted into their respective chlorids,the calcium precipitating in the form of a sulphate, the A lyecontaining but a very small proportion of calcium sulphate in solution,and this is eliminated in the subsequent operation. After separating theprecipitated calcium sulphate from the lye the silver, if any bepresent, can be precipitated by well-known meansas, for instance, bymeans of iodide of potassium or sodiumafter which the iron, in so far asthis is present in the form of a ferro-salt, is eliminated in the formof a hydroxid by means of carbonate of lime in presence of atmosphericair, the reaction taking place in accordance with the followingequation:

The clear lye, after separation of the iron con taining the chlorine ofthe iron salt in the form of calcium chlorid, may now be freed fromnickel, cobalt, and manganese-for instance, in a well-known manner bymeans of chlorine, but preferably by means of hypo IOO nickel by meansof hypochlorite of lime takes place according to the followingequations:

Man ganeseMn()-{ CaC1,0 :Mn 0 CaCl Cobalt2CoO+OaOl O Co O CaOlNickel-2NiO+CaCl O :Ni O +CaCl The solution freed from the metalsreferred to containing essentially chlorid of zinc, sodium chlorid, andcalcium chlorid, is concentrated by evaporation for electrolyticaltreatment, whereby the sulphate of sodium still present in smallquantity or traces is separated, and nearly the whole of the sodiumchlorid is obtained in a solid form. The fact that some of the zincchlorid may go overinto the sodium chlorid is of no moment, since thelatter salt is again used in the process of roasting ores. Hence thiszinc is not lost.

The concentrated mother lye containing zinc chlorid, calcium chlorid,and some sodium chlorid I prefer to treat electrolytically in presenceof zinc and carbon electrodes, metallic zinc being deposited at the zinccathode while the chlorine is evolved at the carbon anode. The ions maybe utilized or sold, the zinc in the form it is obtained or afterresmelting, and the chlorine in a fluid form or in the form ofbleaching-powder, though a portion, at least, of the chlorine may beutilized in my process.

The calcium chlorid remaining in the lye and the non-converted zincchlorid are used in the process. Such additional calcium chlorid as maybe required can be obtained at a small cost from the waste in theammonia soda process.

In case the lyes also contain copper in sufficient quantity to warrantits extraction or to render the same necessary the lye is treated in themanner described in relation to the extraction of zinc, with theexception that either before or after the addition of chlorid of lime tothe solution the silver, if present, and the copper are both eliminatedsuccessively, the former in a well-known manner and the copper by meansof metallic iron, or the copper, if present in large quantity, may beobtained electrolytically together with chlorine and the remainingcopper precipitated by means of metallic iron. The further treatment ofthe lye is then effected as described, in that the iron is removed bymeans of calcium carbonate in the presence of atmospheric air in theform of a hydroxid, and so on.

In the application of the invention to cupriferous lyes rich in copper alarge quantity of metallic iron will be obtained in solution, and as aconsequence the lye will contain a large quantity of calcium chlorid insolution after the precipitation of the iron, so that the remainingcalcium chlorid lye will be sufticient for the conversion of thesulphates in the mother lye, as above set forth.

The described process has many advantages irrespective of its simplicityand of the fact that there are no obnoxious waste lyesin fact, there areno waste lyes-and these advantages consist in that the sodium chloridnot decomposed in the roasting of the ore is also recovered with thesodium by concentration of the lye, as described, in that the calciumchlorid used in the process may be cheaply obtained from the wasteproducts of the manufacture of soda by the ammonia process, whereby thechlorine hitherto lost (and for the economical recovery of which manyfutileattempts have been made) is also utilized. The calcium can bonateemployed in the precipitation of the iron may be as cheaply derived fromthe waste products resulting in the manufacture of caustic potash, whilethe concentration of the lye before the electrolytical treatment maybeeconomically efiected by the use of the exhaust-steam of the works.

Having thus described my invention, what I claim as new therein, anddesire to secure by Letters Patent, is

1. The herein described process of treating zinciferous or cupriferouslyes resulting from the lixiviation of chlorinated roasted ores,

which consists in chemically extracting the metals in the lye, exceptthe zinc, removing the sodium chlorid by concentration of the lye,extracting the zinc and chlorine from the remaining lyeelectrolytically, and etfecting the chemical extraction in such mannerthat the final lye will consist essentially of a solution of calciumchlorid, for the purpose set forth.

2. The herein described process of treating zinciferous or cupriferouslyes resulting from the lixiviation of chlorinated roasted ores, whichconsists in converting the sulphates in the lye into chlorides by meansof calcium chlorid, separating the resulting calcium sulphate from thelye, extracting the silver, if any be present, next the copper byelectrolysis under evolution of chlorine, then chemically such othermetals as may be present in the lye, concentrating the same byevaporation, removing the sodium chlorid therefrom, and subjecting theremaining lye to electrolysis and conducting the operations in suchmanner that a final lye consisting essentially of a solution of calciumchlorid is obtained, for the purpose set forth.

3. The process of treating zinciferous and cupriferous lyes, resultingfrom the lixiviation of chlorinated roasted ores, which consists inconverting the sulphates in the lyes into chlorides by means of calciumchlorid, separating the resulting calcium sulphate, extracting thecopper, iron, and other metals successively from the lye, thenconcentrating the latter by evaporation, removing the solid sodiumchlorid obtained and extracting the zinc electrolytically underevolution of chlorine from the remaining lye, substantially as and forthe purpose set forth.

4. The herein described process of treating zinciferous lyes resultingfrom the lixiviation of chlorinated roasted ores, which consists inconverting the sulphates in the lye into chlorides by means of calciumchlorid,

separating the calcium sulphate from the lye, extracting the silver, ifany be present, converting the iron into a hydroxid by means of asuitable agent as carbonate of calcium,

converting the nickel, cobalt 850. into oxids by means of chlorine,preferably in the form of hypochlorite of lime, whereby an equivalentquantity of calcium chlorid is formed, and concentrating the lye byevaporation, whereby the sodium chlorid is obtained in solid form andthe remaining lye placed in condition for the extraction of the zinc.

5. The herein described process of treating zinciferous lyes resultingfrom the lixiviation of chlorinated roasted ores, which con sists inconverting the sulphates in the lye into chlorides by means of calciumchlorid, separating the calcium sulphate from the lye, extracting thesilver, if any be present, converting the iron into a hydroxid by meansof carbonate of calcium, converting the nickel, cobalt 850. into oxidsby means of chlorine, preferably in the form of hypochlorite of lime,whereby an equivalent quantity of calcium chlorid is formed, andconcentrating the lye by evaporation, whereby the sodium chlorid isobtained in solid form, and extractin g the zinc and chlorineelectrolytically from the remaining solution, whereby a 'final lyeavailable in the process is obtained, substano tially as set forth.

6. The herein described process of treating cupriferous lyes resultingfrom the lixiviation of chlorinated roasted ores, which consists inconverting the sulphates in the lye into chlorides by means of calciumchlorid, separating the resulting calcium sulphate from the lye,extracting the silver, if any be present,in a well known manner, thenthe copper by means of metallic iron, concentrating 40 the solution byevaporation after removal of other metals if any be present in the lye,re moving the sodium chlorid from the lye. and extracting the remainingcopper electrolytically under formation of chlorine, whereby a final lyeconsisting essentially of a solution of calcium chlorid is obtainedafter removal of the iron therefrom, for the purpose set forth.

In testimony that I claim the foregoing as my invention I have signed myname in presence of two subscribing Witnesses.

, HUGO BREWER.

Witnesses:

ANNA SIMON, WILLIAM ESSEMOEIN.

